class A {
	final double PI=3.1415926;//PI是常量
	public double getArea(final double r) {
		//r=r+1;	//非法，不允许对final变量进行更新操作
		return 	PI*r*r;
	}
	public final void speak() {
	System.out.println("您好,How's everything here ?");
	}
}
public class Example5_9 {
	public static void main(String args[]) {
		A a=new A();
		System.out.println("面积:"+a.getArea(100));					a.speak();
	}
}
